An improved cascaded Taylor compensation algorithm for the time mismatch error in high-speed high-precision TIADC is proposed. Specifically, the linear approximation principle is used to estimate the time mismatch error, then an improved cascaded Taylor compensation structure is used to compensate for error. The error compensation module and error estimation module together form a feedback calibration structure to enable real-time estimation and calibration of the time mismatch error. A 4-channel TIADC system with 16 bit and clock sampling frequency of 500 MHz is established in MATLAB for simulation and verification of the time mismatch error calibration model. The experimental results show that when the input signal frequency is in the whole Nyquist frequency band, and after the 3rd order calibration, the SFDR and SNR of the TIADC system are improved by 56.2 and 55.6 dB on average. Compared to the traditional cascaded Taylor compensation structure, the hardware implementation is further reduced in size.