Abstract: [Objective][Method]The study aimed at accurately determining grain number of a spike of wheat in order to provide better technical support to accurately establish technique scheme and summarize experience for high yield, and it was explored by field test. [Result] The results showed that, new method could improve 4 times sample rate, and enhance data accuracy compared to traditional method. Its concrete steps included: in measured wheat field, We selected representative multiple sampling points, and took continuous spike(≥100 number)in every sample point(1m2), and recorded related contents placing in mesh nylon bag；Dried sample and weighed grain, and randomly selected ≥3 portions as repeat number of grain number of a spike; Calculated total grain numbers of sample by sample weight and weight of number every repeat, and sample total grain numbers divided by sample spike numbers obtained grain number of a spike of every repeat; The mean of grain number of a spike of all repeats was grain number of a spike of every sample; The mean of grain number of a spike of all samples was grain number of a spike of sampled wheat. [Conclusion]The new determination method effectively improved sample rate, and more accurately reflected grain number of a spike of wheat in different field. It could effectively reduce error due to heredity, cultivation and environment factors compared to traditional method.