Development and distribution of mucous cells in digestive tract of larval and juvenile (0﹣50 day-old) Paramisgurnus dabryanus was observed and analyzed by the method of histological sections and AB-PAS histochemical staining techniques. Three sections of larvae and juveniles digestive tract were chosen. Ten visions were random selected for measuring the number and size of mucous cells With Image-Pro Plus. All the measured dates were compared with one-way ANOVA using spss19.0. The level of significant difference was set at P < 0.05. The results indicated that there were four types of mucous cells (I, II, III, IV) in digestive tract of P. dabryanus (Fig 1). Mucous cells initially appeared in buccopharyngeal cavity and esophagus at 4 day-old. At 5 day-old, the type of mucous cells in buccopharyngeal cavity and esophagus was mainly II type, and the shape of them were globular or capsular (Fig 1a, b). Mucous cells initially appeared in anterior and middle intestine at 8 day-old, and type of them were I and III type (Fig 1c, d). The type of mucous cells in posterior intestine were mainly II type, and the shape of them were globular (Fig1e).There was a rapid increase of the number of mucous cells in buccopharyngeal cavity and esophagus between 10 and 15 day-old (Table 1). At 15 day-old, mucous cells were widespread in buccopharyngeal cavity and esophagus，and shape of them mainly was rod or globular (Fig 1f, g). The number of all type mucous cells in intestine increased significantly between 15 and 20 day-old (Table 1). Mucous cells were widespread in digestive tract after 20 day-old. Shape of most mucous cells in anterior and middle intestine were rod or capsular, while mucous cells’ shape in posterior intestine were globular or capsular at 20 day-old (Fig 1h ~ j). As the growth of larvae, mucous cells in digestive tract were mainly III and IV types. With larval and juvenile development, intestinal epithelial mucin PAS and AB (pH 2.5 and 1.0) reactions were gradually increased, indicating that the acidic and neutral mucilage of digestive tract secretion increased. And the AB (pH 2.5 and 1.0) reaction strength of anterior intestine and posterior intestine was higher than middle intestine (Table 2). Size of mucus cell in digestive tract is gradually increased. Larvae mucus cells in esophagus were largest in the same day-old, followed by Buccopharyngeal cavity, and were larger than mucous cells in the each part of intestinal (Table 3). At 5-15 day-old, secretion capability of mucus cell in esophagus was stronger than the other part of digestive tract (P < 0.05) (Fig 2). Secretion capability of mucus cell in anterior intestine increased significantly during 10-15 day-old (P < 0.05) (Fig 2). After 15 day-old, Secretion capability of mucus cell in posterior intestine increased significantly. In 20 day-old, secretion capability of mucus cell in middle intestine was weaker than anterior and posterior intestine (P < 0.05) (Fig 2).According to our researches, the sensitive periods of the development of larval and juvenile P. dabryanus were 5﹣10 day-old and 15﹣20 day-old, respectively. Digestive function gradually developed consummately after 20 day-old. In order to improvesurvival rate, it was necessary to strengthen larvae and juveniles daily feeding and management from 5 to 20 day-old.