A small sized and low power consumption physical package of CPT atomic frequency standard developed by us is introduced in the paper. The experiments of locking laser frequency and microwave frequency were carried out and realized with the physical package. By locking laser frequency to atomic absorption spectrum through current negative feedback and locking microwave frequency to electromagnetic induced transparency resonance peak through voltage negative feedback respectively, the locking of the clock frequency of this laboratorial desktop experimental CPT frequency standard is realized. The measurement of the frequency stability of this experimental system demonstrate a performance better than 5×10-11τ-1/2 （1—200 s）.