  As an important candidate theory of gravity, Brans-Dicke theory has been
widely studied. In this paper, we investigate light bending and gravitational
lensing by compact objects in Brans-Dicke theory in weak gravitational field.
Firstly, we present a general formalism for calculating higher-order
corrections to light bending angle and lensing observables for a static,
spherically symmetric and flat spacetime, in which the metric is given in the
isotropic coordinates. Secondly, we apply the general formalism to Brans-Dicke
theory and get the corresponding light bending angle and lensing observables.
Our results show that, although the sums over the low-order correction terms in
magnifications of the primary and secondary images do not dependent on the
theories of gravity, the sums over correction terms with order higher than
three do. Moreover, we show that the total magnification has a non-vanishing
first-order correction, rather than a vanishing contribution concluded in the
literature. We find that the corrections to lensing observables of BD theory
close to those of GR when the parameter $\omega$ tends to $+\infty$ from
$-\frac32$, while opposition occurs when $\omega$ tends to $-2$ from $-\infty$.
