Using the definitions of quantum controlled not-gates and single qubit rotating-gates, we design four kinds of pulse sequences, which are logically equivalent to the nuclear magnetic resonance （NMR） realization of quantum controlled not-gates. Under the condition that the radio frequency pulse duration is much shorter than the interaction time between two nuclear spins, the two-body time-dependent Schr?dinger equation with NMR is approximately solved in the rotating reference frame and the optimal NMR pulse sequence parameter value for the quantum controlled not-gate is given. Meanwhile, according to the Suzuki''s symmetric product formula, the time-dependent Schr?dinger equation is numerically calculated, the performance of these four sequences of quantum controlled not-gates is demonstrated by numerical calculation, and the performance advantages and disadvantages of different pulse sequences are judged.