  We aim to test if a blazar candidate of uncertain-type (BCU) in the third
Fermi active galactic nuclei catalog (3LAC) can be potentially classified as a
BL Lac object or a flat spectrum radio quasar (FSRQ) by performing a
statistical analysis of its broadband spectral properties. We find that 34% of
the radio-selected BCUs (583 BCUs) are BL Lac-like and 20% of them are
FSRQ-like, which maybe within 90% level of confidence. Similarly, 77.3% of the
X-ray selected BCUs (176 BCUs) are evaluated as BL Lac-like and 6.8% of them
may be FSRQ-like sources. And 88.7% of the BL Lac-like BCUs that have
synchrotron peak frequencies available are high synchrotron peaked BL Lacs in
the X-ray selected BCUs. The percentages are accordingly 62% and 7.3% in the
sample of 124 optical-selected BCUs. The high ratio of source numbers of the BL
Lac-like to the FSRQ-like BCUs in the X-ray and optically selected BCU samples
is due to the selection effect. Examining the consistency between our
evaluation and spectroscopic identification case by case with a sample of 78
radio-selected BCUs, it is found that the statistical analysis and its
resulting classifications agree with the results of the optical follow-up
spectroscopic observations. Our observation campaign for high-|\rho_{s}| BCUs ,
i.e., |\rho_{s}|>0.8, selected with our method is ongoing.
