Temperature-resistant visual sand filling pipe with adjustable length

The invention provides a length-adjustable temperature-resistant visual sand-filled pipe which comprises a left plug part, a visual sand-filled pipe part, a right plug part and a sand-filled pipe movement control part, and the left plug part and the right plug part are in threaded connection with the visual sand-filled pipe part and used for injecting fluid into/out of the visual sand-filled pipe part. The visible sand filling pipe part is divided into a porous medium section and a non-porous medium section and is used for observing foam seepage characteristics and form changes of foam fluid in a porous medium and after the foam fluid passes through the porous medium, and the sand filling pipe movement control part can adjust the relative length of the porous medium section and the non-porous medium section. According to the sand-filled pipe, foam seepage characteristics and form changes of foam fluid in a porous medium and after the foam fluid passes through the porous medium under the set oil reservoir temp