Abstract: The high altitude calibration of solar cells is of great significance to study solar cells for space application. This paper presents a measurement scheme to measure the Ⅰ-Ⅴ curves of solar cells at a high altitude. The paper studies the hardware testing system based on FPGA, the method of acquiring the current and voltage data in parallel and the automatic measurement method of software in this system. An algorithm for fitting the current-voltage curve of solar cells based on chaos algorithm and genetic algorithm is proposed. According to the experimental data of ground testing, the curve fitting algorithm is carried out by using solar cell single diode mathematical model. The results show that the fitness value of the chaos genetic algorithm is 4.0289×10^-4, which means that the curve fitting is better than particle swarm algorithm and genetic algorithm.