Abstract: There are provided methods of lining the internal surface of a pipe, which includes first inserting two lining pigs into the pipe and then introducing a batch of resin thereinto, or inserting one lining pig between two batches of a resin, or first inserting a lining pig and then inserting two batches of a resin with another lining pig therebetween, or first introducing a lining pig made of a soft material capable of deforming so as to pass through a narrow-passing section and then introducing a batch of a resin into the pipe, causing the resin to move forward until the front end of the resin reaches an inner end of the pipe, and sucking the resin back from the inner end so as to line the internal surface of the pipe with the resin. There are also provided improved liquid blocking pigs for use in pipe lining treatment, each of such pigs comprises a spherical body made of a soft resilient material and a least one flexible liquid barrier diaphragm interposed in the spherical body.