This paper presents the results of a study of the morphology, ecology and larval development of Phoronis ijima Oka collected from the littoral zone of the Huang Hai (Yellow Sea). Phoronis ijima Oka is most abundantly distributed in the Huang Hai (Qingdao). Judging from its geographical distribution, it can be considered as a Warm temperate species. Adult worms live on muddy stone near low tide level in relatively quiet water; Usually in dense clumps, occasionally in a thin encrusting layer. The spawning season of Phoronis ijima Oka in Qingclao is in November to May:when the temperature of the sea water is between 4-16℃. The fertilized eggs, the two-cell stage and eight-cell stage of cleavage, the larva 'with two tentacles and the larva with four tentacles are obtained from the tentacle crown. We observed larvae of specimen in the dish freeing themselves with four and six tentacles. These larvae (Actinotrocha) swim quickly, rise to the surface, then dive to the bottom of the dish; this movement is frequently repeated. But all larvae died later under laboratory conditions. The larvae with eight tentacles were collected by means of plankton net from Jiaozhou Bay (Qingdao) were reared in the laboratory to complete their metamorphosis. As a result of which, we are able to identify the species as Phoronis ijima Oka. Egg to larva with two tentacles: about four days. Free-swimming period: 10-12 days. Metamorphosis: about two hours.