This essay designed a kind of new seven-core fiber with lower crosstalk and loss,and made space division multiplexing transmission experiment based on this seven-core fiber.It is known that crosstalk has the most serious influence in multicore fiber transmission process.Before the experiment,the affecting factors of fiber crosstalk were analyzed through simulation,such as core space,bending radius,and fiber length.Combined with the simulation analysis,the design scheme of multicore fiber with low crosstalk was obtained.Before the fiber design,various factors of influence crosstalk such as the coreto-core distance,bending radius,fiber length and so on.Based on the simulation analysis,conclusion has made on the design scheme of multi-core optimal fiber with low crosstalk.The space division multiplexing and wavelength division multiplexing technology,was adopted to conduct seven-core optical fiber transmission of 58.7km.The crosstalk of adjacent core was suppressed to as low as 45 d B/km,the attenuation of inner core was 0.24 d B/km,the outer cores’ 0.32 d B/km.Different bit error rate(BER) performances were also studied under different conditions,through reasonably designing the system to reduce the error rate,improve the performance of the system,and realize long distance and large capacity transmission with fiber. This essay designed a kind of new seven-core fiber with lower crosstalk and loss, and made space division multiplexing transmission experiment based on this seven-core fiber. It is known that crosstalk has the most serious influence in multicore fiber transmission process. Ago the experiment, the affecting factors of fiber crosstalk were analyzed through simulation, such as core space, bending radius, and fiber length. Combined with the simulation analysis, the design scheme of multicore fiber with low crosstalk was .Before the fiber design, various factors of influence crosstalk such as the coreto-core distance, bending radius, fiber length and so on. Based on the simulation analysis, conclusion has made on the design scheme of multi-core optimal fiber with low crosstalk. space division multiplexing and wavelength division multiplexing technology, was adopted to conduct seven-core optical fiber transmission of 58.7km. The crosstalk of adjacent cores was suppressed to as low as 45d B / km, the attenuation of inner core was 0.24 d B / km, the outer cores’ 0.32 d B / km. Different bit error rate (BER) performances were also studied under different conditions, through reasonably designing the system to reduce the error rate, improve the performance of the system, and realize long distance and large capacity transmission with fiber.