Background: The effect of therapeutic exercise on cervical flexion relaxation phenomenon (FRP) is questionable. This study aimed at investigating the effect of eight weeks of cervical stability exercise on FRP, pain, and disability in NSCNP patients.Methods: This quasi-experimental study was conducted on 25 subjects with NSCNP. Surface electromyographic signals of the cervical erector spinae (CES) muscles in a sitting position were recorded before and after the intervention. The occurrence of FRP and flexion relaxation ratio (FRR) were analyzed before and after the eight weeks of cervical stability exercise. The low-load craniocervical flexion exercise was performed by the subjects in crook lying position. In addition, the intensity of pain and disability were assessed via visual analogue index (VAS) and neck disability index (NDI).Results: The FRR of CES muscles increased after the intervention. Similarly, the occurrence of FRP increased among NSCNP patients after the intervention. The average changes of VAS, NDI, and FRR were not associated with gender and duration of pain. Moreover, VAS and NDI scores significantly decreased after the intervention. Conclusions: Flexion relaxation phenomenon can be improved via specific stability exercises. The improvement of flexion relaxation phenomenon apparently can pain and disability.