Atomic data for K-shell transitions are essential for modeling the K absorption lines, which have been observed in the spectra of active galaxies by high-resolution X-ray observatories, e.g. XMM, Chandra, and Suzaku. These accurate atomic data are also needed for line identifications and spectroscopic diagnostic of plasmas in laboratory generated by laser or beam-foil method.The atomic code Flexible Atomic Code (FAC) has been used to calculate these data. Relativistic effects and configuration interactions are taken into account in calculations.The K-shell transitions among the configurations of 1s^2^2s^2^, 1s^2^2s2p, 1s^2^2p^2^, 1s^2^2sn'l', 1s^2^2pn'l', 1s2s^2^2p, 1s2s2p^2^, 1s2p^3^, 1s2s2pn'l' and 1s2p^2^n'l', n'<=4, l'<=n' for beryllium-like Si XI have been calculated. The K-shell energy levels, wavelengths, radiative rates and oscillator strengths for Si XI are reported. In order to assess the accuracy of current data, comparison between our results with former experiments and other theoretical works have been made.