LEAD: Joel Steinberg, charged with murder in the beating death of a 6-year-old girl in his Greenwich Village apartment, was allowed to miss a court appearance yesterday because he is afraid of other inmates, his lawyer said.

Joel Steinberg, charged with murder in the beating death of a 6-year-old girl in his Greenwich Village apartment, was allowed to miss a court appearance yesterday because he is afraid of other inmates, his lawyer said.

His lawyer, Ira London, said inmates on buses from Rikers Island had threatened Mr. Steinberg's life and tried to hurt him.

''This case has created a lot of hostility toward Joel,'' Mr. London said.

A spokeswoman for the Correction Department, Ruby Ryles, said a special plastic cage was being built for Mr. Steinberg.

The lawyer spoke after a hearing in which Justice Harold J. Rothwax of State Supreme Court signed a routine order for Mr. Steinberg to give prosecutors hair and blood samples. The defendant had been excused from appearing. Justice Rothwax set Jan. 27 to hear pretrial motions. Mr. Steinberg is charged with second-degree murder in the death last month of Lisa Steinberg, who lived with him and his wife, Hedda Nussbaum, on West 10th Street almost all her life, but who was never adopted.