Soil testing and formula fertilization technology is not only conducive to reduce the application of chemical fertilizers, but also conducive to control agricultural non-point source pollution and to help farmers reduce costs and increase income, which is an important way to achieve sustainable development of agriculture. Based on the rational smallholder theory and a survey data of planting family farms in northeast China, this paper examined the influences of the adoption behaviors of soil testing and formula fertilizer technology by family farms, and explored the income effect of the adoption of the technology by the endogenous switching regression model. Results show that the adoption rate of soil testing and formula fertilization technology is low, only 44.62% of the surveyed farms. Research also finds that the age of the household head has a negative impact on the adoption of this technology, and education level, agricultural technology training, risk preference, business scale, land transfer period, and demonstration farms have significant positive impacts on family farm’s adoption of this technology. In addition, education level, training in agricultural technology, risk preference, and demonstration farms have significant influences on farm income. Large scale family farms have the best income increase by adopting this technology. The study further confirms that the soil testing and formula fertilization technology has a significant positive income effect, which can significantly improve farm income. Therefore, this paper suggests to enhance the promotion mechanism of the soil testing and fertilizer technology, to increase the accumulation of human capital level of family farms, to improve the constraint conditions of the application of soil testing and formula fertilization technology, to improve the risk compensation mechanism, and to advocate the family farm moderate scale management.