  We propose a scheme of quantum secret sharing between Alices' group and Bobs'
group with single photons and unitary transformations. In the protocol, one
member in Alices' group prepares a sequence of single photons in one of four
different states, while other members directly encode their information on the
sequence of single photons via unitary operations, after that the last member
sends the sequence of single photons to Bobs' group. Then Bobs except for the
last one do work similarly. Finally last member in Bobs' group measures the
qubits. If Alices and Bobs guarnnted the security of quantum channel by some
tests, then the qubit states sent by last member of Alices' group can be used
as key bits for secret sharing. It is shown that this scheme is safe.
