La(0.7)Sr(0.3)MnO(3)/La(0.96)Sr(0.04)MnO(3)/La(0.7)Sr(0.3)MnO(3)　magnetic　tunnel　junction　device　have　been　fabricated　on　SrTiO(3)　(STO)　substrate.　A　large　tunneling　magnetoresistance　(TMR)　of　134%　was　observed　from　the　junction　with　an　antiferromagnetic　insulating　barrier　layer　(2　nm)　at　a　temperature　4.2　K.　Current-voltage　(l-V)　characteristic　of　the　junction　is　consistent　with　a　tunneling　process　at　low　temperature.　A　simulation　based　on　Simmons＇　tunneling　model　give　a　barrier-layer　thickness　d　approximate　to　5　nm　and　an　average　barrier　potential　height　Phi　approximate　to　0.1　eV,　respectively.　The　results　indicate　that　the　large　TMR　is　related　to　crystallographic　similarity　between　La(0.7)Sr(0.3)MnO(3)　and　La(0.96)Sr(0.04)MnO(3)　compounds,　which　should　minimize　lattice　mismatch　between　the　electrodes　and　the　barrier　layers.