An adjustable awning has no longitudinal linkage, which makes efficient use of space, can be assembled with a collapsible roof as a whole, increasing the function of the collapsible roof, and can be unfolded together with the collapsible roof, controlled by a mechanism inside the collapsible roof, and the control mechanism can be adjusted to select whether the awning is linked to the roof or not. The horizontal adjustable awning includes an internal control mechanism, a main transmission mechanism and a folding mechanism. The internal control mechanism includes a spring roller, a drive belt, a belt end block and a block snap; the main transmission mechanism includes a pulley, a filament rod, a shade cloth mechanism, a bearing housing, a rack and pinion mechanism and a gear housing; the folding mechanism includes two rotating pushers, two articulated sliders and a protective plate.