Aiming at the design problem of a fractional order PID controller, an improved sparrow search algorithm(ISSA) is proposed to adjust the parameters of the fractional order PID controller. The Chebyshev chaotic map is introduced into sparrow search algorithm(SSA) to improve the population diversity and global search ability of the SSA. The adaptive $ t $-distribution and firefly algorithm are adopted, and the conversion probability $ p $ is set to make them execute alternately, so as to improve the convergence accuracy and optimization performance of the SSA. The 10 benchmark functions, and the results show that compared with the existing four classical algorithms, the ISSA has a great improvement in convergence speed, convergence accuracy and global search ability. Finally, two kinds of controlled systems are simulated and analyzed. Compared with the existing results, the effectiveness and practicability of the proposed ISSA algorithm for solving the fractional order PID controller parameter tuning problem are verified.