Abstract: Space shift keying (SSK) is a novel space multiplexing technique. Multiple transmit units exist while only one transmit unit is active at any given time instance in SSK. It is the position of transmit antennas not transmit symbols that covey information. Although SSK have many advantages, its spectral efficiency is low demonstrated by theory. For higher spectral efficiency, in this paper, we present optical multiple active antennas shift keying (MAA-SSK) as a new modulation scheme, which is based on the generalized spatial modulation (GSM) concept. In MAA-SSK, precoded sequences of symbols are transmitted using more than one antenna and BER performance gain is obtained by optimizing the set of antenna combination. In this paper MAA-SSK model is introduced and its bit error rate (BER) performance is analyzed. The selection method is put forward via maximizing the minimal distance involved. The BER performance of MAA-SSK with and without antenna selection is simulated and compared, which demonstrates the validity of our antenna selection method.