The invention relates to a hot rolling method of a high-strength interstitial-free steel belt. The high-strength interstitial-free steel belt comprises, by weight, less than or equal to 0.0050% of C, 0.10%-0.30% of Si, 0.35%-0.70% of Mn, 0.045%-0.085% of P, less than or equal to 0.008% of S, 0.025%-0.055% of Als, 0.050%-0.070% of Ti, 0.0005%-0.0015% of B, less than or equal to 0.0050% of N, and the balance Fe and inevitable microelements. According to the provided hot rolling method aiming at the high-strength interstitial-free steel belt with the high contents of the Mn, the P and the Ti, the duration of stay of a plate blank in a heating furnace, the furnace temperature of all sections of the heating furnace, the plate blank operation speed during scale removal, the speed of belt penetrating and coiling of a heat coil box, the front section cooling speed in the laminar cooling process and the coiling temperature are controlled, so that the obtained high-strength interstitial-free steel belt is appropriate in strength, uniform in microscopic structure and good in surface quality, the product yield strength is 310-350 MPa, the product tensile strength is larger than or equal to 400 MPa, and the product elongation rate A50 is larger than or equal to 38%.