In this paper, we consider the Bernstein polynomial of the empirical distribution function F-n under a triangular sample, which we denote by (F) over cap (m,n). For the recentered and normalised statistic n(1/2) ((F) over cap (m,n)(x) - E-Gn(F) over cap (m,n)(x)), where x is defined on the interval (0, 1), the stochastic convergence to a Brownian bridge is derived. The main technicality in proving the normality is drawn off into a stochastic equicontinuity condition. To obtain the equicontinuity, we derive the uniform law of large numbers (ULLN) over a class of functions sup(H) |(P-n - E-Gn)h| by domination conditions of random covering numbers and covering integrals. In addition, we also derive the asymptotic covariance matrix for biavariant vector of Bernstein estimators. Finally, numerical simulations are presented to verify the validity of our main results.