This paper overcomes the traditional simulation method which does not consider the coupling effect between tank truck movement and liquid sloshing in the rollover process, simulates the rollover process of tank truck more truly, and calculates the critical value of tank truck rollover more accurately. The data interaction between ADAMS CAR and FLUENT is realized indirectly by using SIMULINK as the intermediate transfer software. Through the secondary development of UDF and S function, data exchange between FLUENT and SIMULINK is realized by means of socket communication. ADAMS CAR transmits the translation velocity and angular velocity of the tank truck to FLUENT, and FLUENT then transmits the resultant force and moment of liquid sloshing to ADSMS CAR, so as to realize the co-simulation of the rollover process of the tank truck by using ADAMS CAR, SIMULINK and FLUENT. The critical acceleration of tank truck rollover was calculated by step steer simulation, and the influence data of liquid sloashing were obtained. The research results can be applied to the safety warning and accident recovery of tank truck. In this paper, the accident recovery of the “June 13” tank truck explosion accident in Wenling section of Shenyang-Haikou Expressway in 2020 is carried out. The calculated results are consistent with the facts, which proves that the results of the co-simulation method are reliable.