A method and device for acquiring a channel with a frequency offset less than half symbol rate is applied but not limited to a DVB-S system. A target channel is selected to obtain a carrier frequency and a symbol rate for programming a tuner to obtain a digital baseband signal. A down-sampling factor is calculated based on the symbol rate for performing a down-sampling operation to obtain a down-sampling signal that passes through a digital matched filter to generate a filtered spectrum. A moving average and spectrum inversion is applied to detect location of the target channel and find two cross points thereby estimating a coarse carrier frequency offset for compensating the tuner and a coarse symbol rate. A fine carrier frequency offset and a symbol rate estimate are estimated for compensating and acquiring the target channel when the target channel is successfully detected.