The invention aims to provide a table lookup optimization method, which comprises the following steps of: a, representing numerical controlled oscillator (NCO) forms corresponding to different television audio carrier frequencies by using a reference form; b, shortening and optimizing the reference form to a 1 / 4 length, and obtaining other non-reference forms from the reference form; and c, further optimizing and storing the reference form according to sine regularities to obtain a sine value and a cosine value by once addressing. The invention also provides a numerical controlled oscillator utilizing the table lookup optimization method, which comprises a form unit, a counting unit, an addressing unit, a splitting unit and a multiplication unit, wherein the form unit is set in a read-only memory (ROM), and stores NCO form data optimized by the table lookup optimization method; the counting unit counts the input television audio carrier frequencies, and takes a count as an index value; the addressing unit addresses the form unit to obtain required NCO form data; the splitting unit splits the required NCO form data into the sine value and the cosine value; and the multiplication unit receives the sine value and the cosine value, and multiplies the sine value and the cosine value by the input television audio carrier frequencies respectively.