【正文】 rom the motive allotment, the loader digger has two kinds of forms: 6 twowheel(rearwheel) to drive and fourwheel(whole round)to drive. the former can’t make use of adherence to weight pletely, making the adhesive strength of motorcycle and ground and the leading force are to descend, but the cost is much lower than the latter. THREE： of the bedrock From the bedrock, among the 3 kinds of mon bedrocks used in the small scaled and multifunction engineering machine, the motive of the miniature loader digger is mostly below 20 KW, the height of the whole machine is 10003000Kg,adopting trackrun structure, the speed dose not reach 5km/h usually used for the yardage processing of small scales, such as farm and park? etc. Because its model is partial to small, cost is higher is 3060KW, the weight is relatively heave, about 50008000Kg, the scooping ability is strong, uses wheeled walks the structure, driven by the whole round, making use of the turn round driving axle or hinge joint, the car speed is higher, reaching to 20km/h, the abroad usually use it as assistance work for the yardage processing and largescale fabricating yard of farm, capital construction, road maintainance? etc. this model’s shape is bigger, the flexibility is worse, generally it hard to adapt the work of narrow and small place. SECOND: local present condition and development trend of loader digger, local technique condition At present in our country the enterprises producing the loader diggers are more than 10 hours, mainly is SHANDONG mechanical engineering, YANTAI mechanical engineering, LIAOLINGCHAOYANG mechanical engineering, LIUZHOU mechanical engineering, XIAMEN mechanical engineering, XUZHOU mechanical engineering, etc.. Currently the product’s year yield is about the history of our small scaled and multifunction loader digger, we can see that our machine has been dropping behind, its development speed is slow. Our country just started to design it by ourselves at the beginning of 70’s in last century, first the BEIJING building mechanical engineering developed successfully W Z 2 A and W Z 2hudraulic pressure loader digger, the YANTAL mechanical engineering manufactures ZW2Aand WZ2B hydraulic loader digger successfully in 1987,After that the FUJIAN mechanical engineering、 SHANDONG GUANGRAO hydraulic pressure engineering develop the loader diggers of WZ25,DFH904WZ,T55Z/W025 respectively. The LIUZHOU excavate loading、 Liuzhou Project Mechanical Limited liability pany developed WZ3025 and WZ2520 loader diggers respectively in july,2020,the SHANDONG Project Mechanical Limited liability pany successfully developed WZ3025 loader digger. 7 The products produced by the following manufacturers are mainly representing the technique level of domestic loader digger. ① the WZ3025 loader digger of CHANGLIN: the engine system adopts ins turbine pressurization engine . the rated output is 63 kNs ,the tap accords with European standard .The turn round for standard truck(front axle)is nondriven swing axle, the bearings adopt imported pieces .Choose to use imported driving axle(back axle)kitted to loader digger. Having nonmaintenance wet brake, which greatly raise the safety and the credibility of the truck belt difference speed padlock raises the draw bar performance of the whole truck .The standard truck driven by twowheel ,can be equipped with a fourwheel drive according to the customer’ demand .The hydraulic system adopts efficient gear pump system, the main parts such as pump, selector valve and redirector, all choose foreign wellknown panies’ products. ② the WZ2520 of YANTAL Project Mechanical Limited liability pany:WZ2520 loader digger takes loading machine for main part, with the head refitted to multipurpose bucket, the back end added excavation device.. The 904WZ loader digger of one drag DONGFANG red is based on the LF90 tractor whose technique is brought from Italian Fiat, with the corollary de