The vertical distribution and changes during day and night of Coilia nasus larvae and juveniles depending on flood tide and ebb tide in the southern branch of Yangtze River estuary. According to the tidal changes, monthly 4 flood trawls and 4 ebb trawls were set at two stations (surface layer and middle layer) from May to September in 2017 using a larval net (1.3 m mouth-diameter, 0.5 mm mesh-aperture) againsting to the current at every station. A total of 369 individuals of Coilia nasus were collected,with developmental stages from pre-flexion larva to juvenile. The average density in the surface layer was 0.851 ind./100 m³ which was higher than 0.145 ind./100 m³ in the middle layer.The average density at pre flexion larva and flexion larva is higher in the surface than in the middle layer, at flood tide than at ebb tide,in the daytime than in the night time. While the average density at post flexion larva in the daytime is lower than that in the night time, at flood tide than at ebb tide. At flood in the daytime, the average density of juveniles is 0 in the surface and 0.14 ind./100 m³ in the middle layer. At ebb tide in the daytime, the average density of juvenile is 0.14 ind./100 m³ in the surface and 0 in the middle layer. The results show some tendency that pre flexion larva and flexion larva trend to the surface and post-flexion larva and juvenile trend to the middle layer. At flood tide in the daytime,post-flexion larva and juvenile trend to the middle layer. At ebb tide in the daytime, post-flexion larva and juvenile trend to the surface. The average density of post-flexion larvae and flexion larvae is higher in the daytime than in the night time.