Abstract: The influences of different production processes on the precipitates and mechanical properties of low alloy high strength steel hot-coil products and continuous-annealing products were studied. Through thermal simulation experiment, it is found that the PTT (precipitation-time-temperature) curve of precipitation of experimental steel is a typical "C" curve shape, and the fastest precipitation temperature is about 800℃. Using different cooling processes to perform production line experiments, it is found that the precipitation of hot coil precipitates can be obviously inhibited when the coiling temperature drops to 500 ℃, laminar cooling and ultra fast cooling have no obvious effect on the precipitation characteristics at this temperature. Through further cold rolling and continuous annealing simulation experiments, it is found that the precipitates corresponding to 500 ℃ coiling are slightly finer and dispersed, and the yield strength and tensile strength are slightly increased by 10-20 MPa.