Regulation of reward signals in the brain is crucial for appropriate evaluation of values and behavioral adaptation. In the fruit fly Drosophila melanogaster, a group of dopaminergic neurons (DANs) in the protocerebral anterior medial (PAM) cluster mediates the reinforcing property of the sugar reward. Recent studies suggest that localized regulation at the presynaptic site of DANs is critical for determining reward in olfactory memory. Cell-type specific visualization of the two dopamine receptors, DopR1 and D2R, also known as Dop2R, revealed their protein localization in presynaptic terminals of the PAM neurons. Based on the sequence similarity, DopR1 and D2R are classified as the fly orthologs to vertebrate D1 and D2 receptors, respectively. Here, we show that DopR1 and D2R in the DAN terminals fine-tune reward signaling for appetitive olfactory memory. In vivo calcium recording of the PAM neurons revealed that the sugar response at the PAM terminals was locally inhibited by D2R, indicating the function as an autoreceptor. Silencing DopR1 and D2R respectively altered appetitive memories in different ranges of sugar concentrations. Interestingly, we found that selective regulation of the PAM neurons by DopR1 and D2R applied to alcohol preference. This dose-dependent tuning by the opposing dopamine autoreceptors may thus represent a general mechanism for defining the dynamic range of reward.