Abstract: To study the influence of porosity,pore structure,confining pressure,water saturation and frequency on v_P and v_S in tight sandstone,we achieved the acoustic properties of six tight sandstones by using pulse transmission method,differential acoustic resonance spectroscopy method and low-frequency strain-stress method,and also obtained the microstructure of the samples by the Micro-CT.Results show that the porosity of tight sandstone samples has fine negative correlation with their density.The correlation between vP and vS and the porosities for dry samples is poor at ultrasonic frequency,but gets better for samples with 100% water saturation.The v_P increases sharply with the increasing of confining pressure.When the confining pressure increases from 0.1 MPa to 20.0 MPa,the v_P both at low and high frequencies increase by nearly 23% due to the closure of the fractures.Acoustic velocities at 1 558 Hz are roughly 3.5%~12.5% lower than ultrasonic velocities at 1 MHz at different water saturation.From dry to fully water saturation,the bulk modulus increases both at 1 MHz and 600 Hz,and has the same increasing trend,which shows a good correlation with the permeability of the samples.