Abstract: sing Translog Stochastic Frontier Production Function Model and a large set of first-hand household level survey data from graingrowers in Shaanxi Province, this paper makes an attempt at both theoretical and empirical analysis on the production technical efficiency of different farmer sizes.Then,Using Tobit Model,this paper makes a regression analysis on exogenous variable that affect technical efficiency. The results show that medium scale of farmers'production efficiency is higher than the small-scale farmers and a large-scale farmers', under the existing technology conditions, the farmer's technical efficiency have a bigger promotion space; In the influence factors, labor age, family non-agricultural income, agricultural income and non-agricultural income ratio, farmers planting land , rentland and scale ,all of these factors have a significant influence on food production technical efficiency; Yet,labor education degree and rentland ratio have no significant effect on efficiency.At last,the paper draws a research conclusion and puts forward some policy suggestions.