Background　The mechanisms and circuits of pain are complex and involve multiple levels in the periphery, spinal cord, and supraspinal brain regions. To solve the pain problem, it is necessary to have a clear understanding of the pain circuits and mechanisms.　Objective　With the development of optogenetics technology, in vivo fiber photometry and miniaturized microscopic calcium imaging, the joint use of these methods is expecting to provide an opportunity for exploring the mechanisms and circuits of pain.　Content　This study reviews the research progress in calcium imaging technology, as well as gene technology, optogenetics technology, most recently-developed in vivo fiber photometry and miniaturized microscopic calcium imaging techniques in pain research.　Trend　This review summarizes new advances of pain circuitry and mechanisms using joint use of these new technologies. The combined use of these methods provides an unprecedented opportunity to explore complex spinal pain circuits and mechanisms. With the continuous advancement of technology, it is believed that people will eventually solve unknown problems related to pain.