A method and device for estimating a Gaussian white noise power in a channel and a receiver are provided. The method includes performing a multi-path search on a received signal to find out paths of the signal; performing a noise estimation on one of the paths to acquire a total noise power of the path; performing an inter-path interference noise estimation on N paths spaced apart from the path by an integral number of chips to obtain an inter-path interference noise power of a single path of the signal, where N is an integer greater than or equal to 1; and subtracting the inter-path interference noise power from the total noise power to obtain the Gaussian white noise power. Through the technical solution of the disclosure, the Gaussian white noise power in a channel is obtained with a higher accuracy, so that the performance of equalization is enhanced.