The invention discloses an 800MPa grade automobile box steel and a production method thereof. The production method comprises the steps of heating, rough rolling, finish rolling, cooling and coiling; the slab adopted contains the following components in percentage by mass: 0.08-0.12% of C, 0.20-0.40% of Si, 1.40-1.60% of Mn, less than or equal to 0.025% of P, less than or equal to 0.010% of S, 0.040-0.060% of V, 0.090-0.120% of Ti, greater than or equal to 0.015% of Als, less than or equal to 0.004% of N and the balance of Fe and inevitable impurities. The steel is strengthened by both vanadium and titanium and a precipitation strengthening effect can be developed more thoroughly, and the overall properties of the steel plate can be improved; besides, the load of rolling can be reduced thoroughly and the production difficulty can be reduced; the steel has the characteristics of low cost, high quality and easiness in machining. According to the method, the precipitation of carbon and carbonitrides, the recrystallization of the austenite and the deformation state of the austenite are controlled by controlling the tapping temperature of the rolled steel, the temperature of the intermediate slab, the finish rolling temperature and the coiling temperature; the strength index and the overall properties of the obtained product are guaranteed, and the product is low in production cost and easy to machine.