  We present the analysis of simultaneous multicolour $uvyI_{\rm C}$ photometry
and low-resolution spectroscopy for the rapidly rotating $\beta$ Cephei star SY
Equ. From the photometric time series, we confirm the dominant pulsation
frequency, $f_1$ = 6.029 d$^{-1}$, and we find an evidence for two additional
modes. In spectroscopy, the highest peak occurs at $f_{\rm a}$ = 0.197 d$^{-1}$
or its alias 0.803 d$^{-1}$. It can be interpreted either in terms of a binary
motion or as the $g$-mode pulsation. In addition, we reveal the pulsation mode
with frequency of about 6.029 d$^{-1}$, i.e. the same which dominates
photometric variations, and a few new candidates. For the dominant frequency we
obtain mode identification from the combined photometric and spectroscopic
observations. From non-adiabatic pulsation calculations, we show that the
frequency of the dominant mode in SY Equ is consistent with the stellar models
of much lower effective temperatures than used in many papers.
