The upper limit of the e+e− partial width of X(3872)

The e+e− decay partial width of the recently observed state, X(3872), is estimated using the ISR data collected at s=4.03 GeV in e+e− annihilation experiment by BES at BEPC. It is found that Γe+e−Bπ+π−J/ψ<10 eV at 90% C.L. if the JPC of X(3872) is 1−−. Together with the potential models and other information, we conclude that X(3872) is very unlikely to be a vector state.