  In this paper an analytical theory is used to complete the transmission
spectrum of HD189733b from near-ultraviolet to infrared (0.33 - 7.85 $\mu m$).
The model suggests a new approach which take into account the quantity of light
transmitted through the planetary atmosphere and the thermal emissions from the
night side of the planet, to describe the transmission spectrum of HD189733b in
photometric study. The availability of measures in different wavelengths has
allowed us to validate our model with more efficiency. We found an agreement
between our transmission spectrum model of HD189733b and data from the infrared
to the UV. The model predicts a value of $R_p /R_\star$ $= 0.1516$ at $7.3 \mu
m$, which is a low value compared to all observations at different wavelengths.
We interpreted this value by a fluorescence emission from sulphur dioxide
($SO_2$). Therefore, the likely presence of these molecules in the atmosphere
of HD 189733b. The second objective of this paper is to study the effect of
starspots on the transmission spectrum of this hot-Jupiter. To reach this goal,
we developed an analytical theory considered as an extension of the approach
proposed by Berta et al. (2011). The model shows clearly that the unocculted
spots would significantly increase the transit radius ratio at visible and
near-ultraviolet wavelengths, while having a minimal impact at infrared
wavelengths. Therefore, the wavelength dependence of the spots effect has been
clearly shown by this new model. At the end of this paper, we reported the way
in which this model can provide an estimation of the percentage of the
unocculted spots area relative to stellar disk area for an observation of
HD189733 performed in a given epoch and at a given wavelength.
