A scheme of linear frequency-modulated signal generation based on optoelectronic oscillator combined with electrical frequency-selected cavity is proposed. The electrical frequency-selected cavity is composed of the electrical amplifier, attenuator, and phase shifter. By adjusting the bias voltage of the phase shifter in the electrical frequency-selected cavity and utilizing the frequency pulling effect between the output signal of optoelectronic oscillator and the output signal of electrical frequency-selected cavity, the linear frequency-modulated signal with a central frequency of 8.3 GHz can be produced, for which the frequency range is as large as 550 MHz, the tuning rate reaches about 5.5 MHz/μs, and the time-bandwidth product is up to 5.5×10 ⁴ (bandwidth 550 MHz, duration 100 μs). Its phase noise depends on phase noise performance of the optoelectronic oscillator, and the frequency range depends on the bias voltage range of the phase shifter. Compared with current methods, the system structure is relatively simple. Linear frequency-modulated signal generated by this scheme has high spectral purity, and its low phase noise is -116 dBc/Hz@10 kHz.