[Objectives]   To determine the developmental duration from egg to adult, fecundity and longevity of Halyomorpha halys adults, and describe the morphological characteristics of each nymph instar. [Methods]  Individual egg masses of H. halys were hatched in a Petri dish. First to 5^th instar nymphs were individually reared and checked after each molt to record their developmental duration and morphological characteristics. The fecundity and lifespan of H. halys adults were measured by rearing male and female pairs. All experiments were conducted at (25±1) ℃, 65%±5% RH, under a 16L∶8D photoperiod. [Results]  The developmental duration of H. halys from egg to adult was (44.98±2.54) d. The duration of the egg stage was 6.90 d, and the hatching rate was 96.06%. The total duration of the nymph stage was (38.08±2.49) d, and that of the 1^st, 2^nd, 3^rd, 4^th, and 5^th instars was (5.41±0.17), (9.17±0.15), (6.73±0.16), (7.46±0.49) and (9.28±0.32) d, respectively. The average survival rate of nymphs was 59.76%. The mean longevity of females and males was (30.80±2.41) and (36.56±2.82) d, respectively. The lifetime fecundity of H. halys females was 83.80 eggs on average. The duration of the pre-oviposition and oviposition periods was 11.80 and 14.08 d, respectively. 1^st instar nymphs are usually yellowish, brown or orange in color, with a body length of (1.93±0.03) mm and width of (1.43±0.02) mm. 2^nd-5^th instar nymphs are often black (not as colorful as 1^st instar nymphs). The 2^nd instar has a black chest dorsal area without yellow freckling, black tibiae without white spots and a body length and width of (2.52±0.05) mm and (1.73±0.03) mm, respectively. The 3rd instar has a black chest dorsal area with yellow freckling, black tibiae with white spots or annulation, and a body length and width of (4.29±0.05) mm and (2.93±0.06) mm, respectively. The 4th instar has wing buds that extend to the edge of the posterior thorax, black tibiae with white annulation, and a body length and width of (6.46±0.10) mm and (4.46±0.08) mm, respectively. The 5^th instar has very obvious wing buds reaching to the end of the posterior margin of the 2nd ventral segment, black tibiae with white rings, and a body length and width of (9.25±0.19) mm and (6.18±0.16) mm, respectively. [Conclusion]  The developmental duration of H. halys from egg to adult was (44.98±2.54) d and the survival rate was 57.60%. The lifetime fecundity was 83.80 eggs per female. The developmental stage of wing buds and the presence of white annulation on the tibiae are key morphological characteristics for distinguishing different nymph instars.