In this paper, in-situ bifunctionalized carbon dots (B-N-CDs) with boronic acid and amino groups were prepared in a simple hydrothermal method using 3-aminophenylboronic acid as the sole precursor. The high quantum yield of B-N-CDs is as high as 67%, which was even observed under daylight excitation. B-N-CDs exhibited obvious fluorescence enhancement to trace dopamine in the range of 1 pM to 1 μM with a detection limit of 0.1 pM (S/N=3), which is two orders of magnitude sensitive than that of nowadays fluorescent sensors. The excellent sensing performance is based on the interaction of two functional groups with DA. This dopamine probe owned advantages of high sensitivity, superior selectivity, good reproducibility and simplicity. Moreover, the analytical reliability of this dopamine sensor was demonstrated in human serum samples.