The present invention provides an abamectin batch fermentation optimizing process, which is improved on the basis of the process for producing the abamectin by the streptomyces avermitilis batch fermentation, wherein, the carbon source proportion in the fermentation solution is 8-11 % during fermentation initial stages, when the fermentation is performed for 20-30 hours, the mixed solution containing glucose and starch is added, so that the carbon source proportion in the fermentation solution keeps 8-11 %; after fermenting 50-60 hours, the adding of the mixed solution containing glucose and starch is stopped, the sterile water is added, the added volume of the sterile water is 2-10 % of the total volume of the added primary fermentation solution; after fermenting 175-185 hours, 15%-20% fermentation solution is added, the residual fermentation solution is added with nutrient solution, the carbon source proportion in the fermentation solution keeps 1-4 %, the fermentation period is completed. The abamectin batch fermentation optimizing process provided by the invention improves the utilization ratios of the fermentation process, the fermentation equipment and the raw materials mainly by the optimization of the material compensating process.