The invention relates to a plane strain tunnel surrounding rock model inside and outside pressure loading device and observation system. The plane strain tunnel surrounding rock model inside and outside pressure loading observation system includes a tunnel surface pressure loading system, a surrounding rock lateral pressure loading system and an optical observation system. The tunnel surface pressure loading system is composed of an internal capsule, a loading cylinder, a first six-way valve, a first pressure regulating valve, a first pressure reducing valve and the like; the internal capsule is composed of a rubber film, a gas tap, a sealing bolt, sealing ball, a bottom limiting plate and a clamping ring; and a high-pressure pipeline extends to the bottom of the internal capsule through the sealing bolt and the center hole of the gas tap, and is fixed to the bottom limiting plate at the bottom of the internal capsule. The surrounding rock lateral pressure loading system is composed of lateral capsules, lateral pressure loading plates, a second six-way valve, a second voltage regulating valve, a second pressure reducing valve, a base, lateral box connecting plates and so on. The optical observation system is composed of a digital camera, a computer, a digital image correlation method program or software. With the device and observation system of the invention adopted, a large amount of reliable data can be provided for mechanism research of tunnel surrounding rock damage and instability and the formulation of preventive measures of tunnel rock burst. The device and system of the invention have the advantages of compact structure, convenient operation and low cost.