In order to overcome the problem of the electronic bottleneck in the traditional arbitrary waveform generation method, the technology type, characteristics and application background of the radio frequency arbitrary waveform based on microwave photonics were analyzed. A triangular waveform generation with frequency doubling based on parallel Mach-Zehnder modulator was adopted, and the theoretical analysis and simulation verification were carried out. The root mean square error was introduced to evaluate the output signal and the ideal waveform. The results show that, the triangle wave signal of 20GHz can be generated by 10GHz driving signal. The root mean square error is 0.038, which means the output signal is in good agreement with the ideal signal. Compared with other methods, the method can generate frequency doubling triangle wave, and the signal waveform agrees well with the theoretical waveform. It has guiding significance for the future generation of radio frequency arbitrary waves based on microwave photonics.