Over two-dimensional Folded Optical Orthogonal Coding (FOOC) network, a simple threshold detection scheme is illustrated to detect the number of simultaneous network users and to adjust the detection threshold value instantaneously. A special wavelength called pilot wavelength is added into the original transmission patterns of every network user. At the receiver, we can acquire the number of simultaneous network users from the power of the pilot wavelength. Consequently, by adjusting the detection power threshold to the optimum threshold value, we can decrease the bit error rate (BER) and improve the system performance for the discussed two- dimensional optical code-division multiple-access (2D-OCDMA) network. Compared with conventional network system adopting prime codes or modified prime codes, the proposed FOOC network with pilot wavelength threshold detection shows an enhanced BER performance and supports more simultaneous network users.