The invention discloses a method and system for obtaining a raised-frequency standard cosine function sequence of electric power signals. The method comprises the following steps: a preliminary sequence length and a preliminary sequence of electric power signals are obtained; frequency preliminary testing is carried out on the preliminary sequence to set a reference frequency; a unit cycle sequence length and the preset sequence length of the electric power signals are obtained; a first-time forward/reverse-folded sequence is further obtained; a first-time average initial phase is obtained according to the initial forward/reverse-folded sequence; according to a first-time phase comparison value between the first-time average initial phase and +-Pi/4 and a new start point, a second-time forward/reverse-folded sequence and a second-time average initial phase are obtained; according to the second-time forward/reverse-folded sequence and the second-time average initial phase, a zero initial phase standard cosine/sine function modulation sequence is obtained; a third/fourth multiplicative sequence is further obtained; and finally according to the third/fourth multiplicative sequence, the zero initial phase standard cosine function sequence with a raised-frequency is obtained. The method and system of the invention can raise the accuracy degree of sine parameter calculating, and is suitable for application.