Abstract:9 groups of different small packages were designed for modified atmosphere storage of Laiyang pear by orthogonal experiment， and the changes of gas composition and the composition of balanced gas in the differ－ ent packages were measured. The regression equation were established to describe the relationship between e－ quilibrium gas composition and influencing factors by ternary quadratic regression analysis. Known Laiyang pear suitable gas composition is 3.2 %CO2 and 14.0 %O2， modified atmophere small packages could be easily de－ signed through the regression equation to meet the different specifications of Laiyang pear.