  In this paper, we use a set of observational $H(z)$ data (OHD) to constrain
the $\Lambda$CDM cosmology. This data set can be derived from the differential
ages of the passively evolving galaxies. Meanwhile, the $\mathcal
{A}$-parameter, which describes the Baryonic Acoustic Oscillation (BAO) peak,
and the newly measured value of the Cosmic Microwave Background (CMB) shift
parameter $\mathcal {R}$ are used to present combinational constraints on the
same cosmology. The combinational constraints favor an accelerating flat
universe while the flat $\Lambda$CDM cosmology is also analyzed in the same
way. We obtain a result compatible with that by many other independent
cosmological observations. We find that the observational $H(z)$ data set is a
complementarity to other cosmological probes.
