Abstract: The Fourth Plenary Session of the 19th CPC Central Committee clearly pointed out that changing the growth mode of farmers' income is the key in the field of agricultural economic construction in the future.At present,the squeezing effect suffered by the low-income farmers has led to the aggravation of the income differentiation of rural residents in our country,and the widening gap between high income and low income in rural areas and the uneven growth of farmers' operating income have become the major components of the "new agriculture,rural areas and farmers" problems.As an important concept in the classical economic growth model,"learning by doing" is the main content of the technological endogenous growth model.At present,there are significant internal differences in farmers' operating income in China,and the effect of "learning by doing" on agricultural operating income has become increasingly prominent.It is of great practical significance to study the mechanism of "learning by doing" effect on the formation of farmers' internal income gap.Based on the Cobb Douglas function model,the effect of "learning by doing" is embedded into the factor of human capital,and the income difference between fishermen and non-fishermen in China is decomposed through empirical research.It is concluded that the effect of "learning by doing" can significantly promote the income growth of fishermen and farmers.This paper puts forward some policy suggestions,emphasizing that the government should strengthen the training and guidance of agricultural production practice in order to enhance "learning by doing" effect in the growth of farmers' income,providing ideas for solving the problems such as the structural imbalance in the income growth of farmers and the widening gap between the rich and the poor.

Key words: farmers, income gap, "learning while doing" effect, fishermen