The invention provides a preflushing CO2 fracturing site ground pipeline anti-freezing construction process and a construction device. The construction process comprises the following steps that S1, amain fracturing truck is connected with a CO2 storage tank; S2, a conventional fracturing fluid pipeline is prepared; S3, a high-pressure pipeline is connected; S4, testing pressure is carried out; S5, preflushing CO2 fracturing is completed, and a pump is stopped; S6, purging of the high-pressure pipeline and a low-pressure pipeline is carried out; S7, a water pipeline is arranged for replacement; S8, circulation heating of an anti-freezing fluid is carried out; and S9, conventional hydraulic fracturing is carried out. According to the preflushing CO2 fracturing site ground pipeline anti-freezing construction process and the construction device, after the preflushing liquid CO2 is injected, nitrogen control pressure replacement and anti-freezing isolation fluid circulation are carried out firstly, and then hydraulic fracturing is carried out, so that the preflushing CO2 fracturing construction is completed by using one set of fracturing equipment, the problem of pipeline low-temperature ice blockage existing in the previous preflushing CO2 fracturing construction is solved, and the purposes of reducing the cost, improving the efficiency, and achieving the safety and high efficiency construction are realized.