Isotridecanol polyoxyethylene-7 ether (E1307) was synthesized by CH3OK catalyzed ethoxylation of iso-tridecanol and ethylene oxide in order to improve the qualities of the products with a broad polydispersity to replace the product with a narrow polydispersity. The effect of the reaction parameters on the product quality, especially the lowest transparent temperature and wetting power, were well investigated, and the experimental results showed that the moisture and the catalyst dosage were the two main influence factors. Moisture was removed as far as possible from isotridecanol under vacuum at 100 oC for 1 h, and then the ethoxylation was catalyzed by CH3OK (0.3%wt) at 120 oC and 0.3 MPa EO, and the product of E1307 was obtained with the lowest transparent temperature of 10 oC and wetting power of 163 s which is superior to the commercial product with a narrow polydispersity.