Abstract: Swell characteristics and wave spectra were studied based on in situ measurements in a Peru sea area off the Pacific coast. The sea is mainly affected by long-period swells from the Pacific Ocean, with a maximum spectral peak period of more than 20 s. A strong linear correlation between the characteristic wave heights and the mean period of swell was obtained by correlation analysis. The joint distribution of wave heights and periods, and the relationship between each characteristic wave heights and the mean period of swell were fitted, which can be used to estimate the characteristic wave heights of swell. Three wave spectral models were adopted to fit the measured wave spectra using the nonlinear least squares method, and it is found that the fitting results of the Ochi-Hubble spectra are more consistent with the measured spectra, with a correlation coefficients around 1.0, and the overall errors of the fitting results for the significant wave heights and the spectral peak periods are all within 2%. Comparing the combined results of wave spectra shape, correlation coefficients and wave characteristic parameters, it is concluded that the Ochi-Hubble spectrum is better to describe the swell spectra.