The invention discloses a method for improving a sulfurous method production process in a cane sugar factory. Active carbon is taken as an auxiliary clarifying agent to perform physical impurity removal and decoloration on serum, filtered serum, crude syrup or triose remelt syrup led out from the sulfurous method sugar production flow, and the secondary sulfur smoke process is eliminated further, so the problem of secondary sulfur smoke troubling the sugar industry for a long term is solved, the quality of whiter granulated sugar is improved fundamentally, and the high-quality whiter granulated sugar with low sulfur dioxide and low color number is produced. The method comprises the following steps of: leading the serum, filtered serum, crude syrup or triose remelt syrup out of the conventional production flow into a reactor; adding the active carbon accounting for 0.5 to 3 mass percent of the syrup in the reactor, reacting at the temperature of between 60 and 90 DEG C for 15 to 30 minutes, and performing physical adsorption, impurity removal and decoloration; and discharging sugar liquor after the adsorption from the reactor, and making purified serum, filtered serum, crude syrup or triose remelt syrup subjected to secondary filtration and solid-liquid separation by using a plate-and-frame filter press and a precision filter enter the conventional production flow again.