  This paper is concerned with the construction of algebraic geometric codes
defined from GGS curves. It is of significant use to describe bases for the
Riemann-Roch spaces associated with totally ramified places, which enables us
to study multi-point AG codes. Along this line, we characterize explicitly the
Weierstrass semigroups and pure gaps. Additionally, we determine the floor of a
certain type of divisor and investigate the properties of AG codes from GGS
curves. Finally, we apply these results to find multi-point codes with
excellent parameters. As one of the examples, a presented code with parameters
$ [216,190,\geqslant 18] $ over $ \mathbb{F}_{64} $ yields a new record.
