Abstract: The computer random simulation method was applied,as a new attempt,toinvestigate the sampling size required in estimating the paddy soil cone-index iNthis paper. The results indicated that the sampling size formula for NormalDistribution was applicable to paddy soil cone-index which follows Weibulldistribution. For problems with statistical characters,the computer random simulationmethod can help to reduce enormously the number of time and money-consuming ex-periments required,and be widely used in the area of agricultural engineering.