The invention aims to provide a method for oil and gas detection by utilizing seismic data instantaneous frequency attribute, which comprises the following steps of: acquiring and recording seismic initial data; carrying out generalized S transformation on the data in a frequency domain to obtain the time-frequency spectrum of each sampling point thereof, and determining the frequencies respectively corresponding to 15 percent and 35 percent of the total energy in the time-frequency spectrum as the initial frequency and the final frequency for computing low-frequency-band absorption attenuation gradient; after taking a natural logarithm from the time-frequency spectrum p (Tk, f) between the initial frequency and the final frequency and fitting by utilizing a least square method to obtain the low-frequency-band absorption attenuation gradient of the sampling point; and corresponding a position with strong low-frequency-band absorption attenuation gradient to a favorable oil and gas contained area, and determining an oil and gas detection result. The invention has lower requirements for signal-to-noise ratio, strong time-frequency resolution capability, simple algorithm and high computational efficiency.