The first-order spatial coherence of ultracold Bose gas above the phase transition temperature in static-magnetic trap is investigated by using phase grating produced by one dimensional optical standing wave field. The interference patterns of thermal atoms are calculated in theory, and the interference patterns of ultracold atomic gas above the phase transition temperature are also obtained by experiments. By comparing the contrast of interference patterns of atomic gas in theory and experiment, it’s found that when the temperature of ultracold atomic gas is very close to the phase transition temperature, coherence of the atomic gas is better than that of thermal atom. With increasing of temperature, the coherence of atomic gas decreases gradually, and it is the same as that of thermal atom finally.