Cassava starch was used as raw material to prepare sour cassava starch (SCS) by lactobacillus fermentation. The effect of different drying technologies including hot air drying (HA), heat pump drying (HP), vacuum freeze drying (VF), spray drying (SD), sun-drying (S) on the quality characteristics and particle structure of SCS was investigated. The results showed that SCS dried by HA and HP had higher yield, better color, lower moisture content, lower gel hardness and lower gumminess. The SCS particles surface were rough, closely arranged and unevenly distributed, and with obvious curl and wrinkle. The SCS dried by VF had the highest yield and the lowest moisture content. It could retain nutrients better and had the best color. The particles were loose and uniform distribution, and some particles surface were collapsed and folded. The SCS dried by SD had the lowest yield, fat content, protein content, acidity, gel springiness and cohesiveness, whereas it had the highest ash content, L* value and pH value. The particles were serious aggregation and nonuniform in distribution, and the round depressions and folds occurred on the surface. The SCS dried by S had the highest moisture content, amylose content, a* value, b* value, whiteness index, gel texture properties (hardness, gumminess, springiness and cohesiveness) and comprehensive scores, whereas it had the lowest ash content, total starch content, amylopectin content and L* value. The particles were uniformly distributed and some complete particles were observed. In summary, the best quality characteristics and particle structure of SCS products could be obtained by S, because of the mild dry conditions and then followed by SCS products obtained by VF. The results of this study provided theoretical basis and technical reference for industrial drying, processing and utilization of SCS.