Sea-level variability in the Sakhalin shelf area is studied. The wavelet-analysis of time series is more preferable in comparison with the traditional spectral one because it gives more flexible technical equipment of signal processing. Altimetry information is received from satellites ERS-1, ERS-2, Jason and TOPEX/POSEIDON and represents sea-level anomalies with 7 day step-type behaviour from October 14, 2002 till January 05, 2005. One must find which scales (or frequencies) determine variability of a sea-level in different time intervals. The contributions of annual and semiannual fluctuation in variability of the ocean level are given. It enables to find a direction of energy transfer fluctuations on scales using inclinations of energy maxima areas. It is shown that the opportunities of the wavelet-analysis open wide prospects to study oceanographic characteristics.