The mathematical background of the rotary spectral estimation of the ocean current vector and the related rotary variates are described briefly in this paper, some achievements in the confidence intervals of the rotary spectral estimator of the vector are summerized. On this basis, the expectation and variance expressions for the autospectral estimator of the rotary spectrum of vector are derived by resorting to some hypotheses and results of the scalar spectral estimator. And then its confidence interval is given. Finally, some computation examples for the rotary spectral estimator of vector are furnished.