Many studies showed NAC transcription factors play an important role in fruit ripening. Moreover, sucrose and starch metabolism is also closely related to fruit ripening. However, there are a few studies focus on whether NAC regulates sucrose and starch metabolism to influence fruit ripening. In this study, virus-induced gene silencing (VIGS) of SlNAP1 suppressed fruit ripening and delayed color transformation. The chlorophyll (including Chla, Chlb, and Chla+b) degradation and carotenoid synthesis in SlNAP1-silenced fruits were dramatically suppressed. Silencing SlNAP1 decreased soluble sugar and reducing sugar accumulation in fruits, and increased starch content. The activity of starch degrading enzymes, including α amylase (AMY) and β amylase (BAM) was significantly lower in SlNAP1-silenced fruits than in the control fruits, whereas denosine diphosphoglucose pyrophosphorylase (AGP) activity was significantly higher. In addition, the expression of starch degradation-related genes (SlAMY1, SlAMY2, SlBAM1, SlBAM7, SlGWD, SlPWD) in SlNAP1-silenced fruits was significantly suppressed, while starch synthesis-related genes (SlAGPase1, SlAGPase2) was significantly increased. Compared with the control fruits, SlNAP1-silenced fruits showed significantly lower sucrose and glucose content. The expression level of sucrose and glucose metabolism-related genes such as Slsus1, Slsus3, SlSPS, SlHxk1, SlHxk2, SlPK1, and SlPK2 was significantly lower in SlNAP1-silenced fruits than in the control fruits. Overall, this study revealed that SlNAP1 gene might positively regulate fruit ripening by influencing carbohydrate metabolism.