Berry phase and topology of the Bloch wavefunction, originating from the interplay of internal quantum attributes of crystal electrons1, holds great significance in classifying novel quantum phases2,3 and endowing emergent functions4. In quantum materials with broken time-reversal or spatial-inversion symmetry, Bloch electrons in motion necessarily carry a geometric phase, and define the topological states2,3,5 and various quantum and nonlinear Hall effects6,7. Recent advances in light-wave-driven optical harmonic emission enable the observation of the rapid evolution of Bloch electrons on a subcycle time scale 8-13 and empower the harnessing of electron dynamics associated with Berry phase effects14,15. However, the correlation between subcycle electron motion and the accumulation of the quantum phase in geometric aspects of the evolving Bloch waves has not been observed. Here, we demonstrate that the Berry phase can be measured and manipulated in topological surface states using two-colour high-harmonic spectroscopy16. This is achieved by introducing a weak second harmonic field with a precisely controlled time delay to perturb the phase evolution of Dirac fermions and thus provide access to the Berry phase. Furthermore, we observe an overwhelming Berry phase effect that deforms quantum pathways of electron-hole pairs. Our observation demonstrates the ability to harness the electron spin using lightwaves in quantum materials with strong spin-orbit interaction, in addition, enhances the application of light-wave-driven spintronics and topological electronics.