We employ a sample of 362 flat-spectrum radio quasars (FSRQs) to calculate their integrated luminosities by integrating the spectral energy distribution (SED)constructed with multi-band (radio, IR, optical, UV and X-ray) data. We compare these luminosities with those estimated from monochromatic luminosities by multiplying them by the conventional bolometric correction factors. Our analysis shows that the integrated luminosities calculated from the SED are much larger than the bolometric luminosities estimated from monochromatic luminosities. Their departing behavior tightly correlates with radio luminosities. The relations between integrated and monochromatic luminosities are explored, which are regarded as empirical relations that might be more suitable to be applied to estimate integrated luminosities of FSRQs from their monochromatic luminosities.