This paper firstly transforms the proper time (Novikov coordinate time)formula of the free-falling particle in the Schwarzschild black hole field from the form in the natural unit system to the form in the international system of units. Then，according to Newton's second law and the law of universal gravitation，the absolute time formula experienced by the free-falling particles is derived，which proves that the proper time of free-falling particle in general relativity is exactly equal to the absolute time given by Newtonian mechanics. Finally，a special case is calculated for the time that free-falling particle experience inside and outside the black hole.