On the basis of basin-planting experiment, the tests have contrasted the control ratio of 10 kinds weed killer to Murdannja keisak, and have analysed the relation of control ratio and paddy output. Show as a result: using 50%Machete before transplanting rice seedlings is best, and the control ratio with quantity of weed reaches 90%. And the control ratio with weigh of weed all reach 90% more by using 53%Mefenacet+Bensulfuron, 50%Machete and 30% Butachlor+Oxadiazon.The control ratio with weigh of weed by using 1%Pyanchor after transplanting rice seedlings reaches 95% more. 53%Mefenacet+Bensulfuron , 1%Pyanchor and 50%Machete had the best output. They respectively increase production 74.41%, 58.27% and 57.51% than CK. The direct Path coefficient of effective fringe quantity to paddy output is the biggest. It is 0.716638. The indirect Path coefficient of the control ratio with quantity of weed , the control ratio with weigh of weed and tillered quantity by effective fringe quantity to paddy output are bigger. They are 0.525439, 0.583343 and 0.667333.