For　Space-Time　Block　Code　(STBC)　systems　with　unknown　co-channel　interference　in　multi-cell　environment,　focusing　on　the　problem　that　the　Capon-style　receivers　will　result　the　self-interference　in　the　STBC　codeword　from　the　finite　samples,　a　robust　linear　receiver　is　proposed.　Based　on　the　orthogonal　structure　of　the　STBC,　the　self-interference　in　the　STBC　codeword　is　first　canceled　with　the　orthogonal　projection.　Then　Capon　receiver　is　used　to　suppress　the　unknown　interference.　Simulation　results　are　presented　to　demonstrate　the　significant　gain　obtained　by　the　proposed　linear　receivers　over　the　conventional　Capon　receiver.