Numerous workers have adopted the flexible working approach due to its accommodating and job-sharing features, which play a key role in easing the employment pressure and maintaining socio-economic sustainability in China. This paper will study the impact of work experience on the income of flexible workers and the characteristics of impact mechanism. We use micro survey data from CFPS2020 to analyze flexible workers in China. This study found that, firstly, while the feature of flexible employment may be very different from formal employment, its relationship with work experience and income is as significantly correlated as it is for formal employment with a rise–fall, inverted U-shaped trend, but the return on work experience is lower than the employment level in the labor market. Secondly, there is an income gap between genders, especially in physical labor-intensive forms of flexible work; women can gradually narrow the gender income gap through continuous learning. Thirdly, the return on work experience in the older age group is lower than that in the youth group of flexible workers, and this may be due to the dynamic evolution of the elimination of existing work experience and the accumulation of new work experience. Fourthly, in contrast with the findings of the labor market as a whole, the trend of work experience return in flexible employment is reversed; the low-income group’s return rate of work experience is higher than that of the high-income group, and it can be seen that flexible employment is conducive to the development of new and young workers.