In recent times, engineering education has increasingly emerged as a valued kindergarten practice. Engineering teaching in play brings challenges for Chinese kindergarten teachers. An educational experiment (EE) was conducted to help Chinese kindergarten teachers face this challenge. Qualitative data including video data and interview transcripts were collected in a public kindergarten located in a Chinese provincial capital city. Participants included one focused teacher and 28 children aged four to five years. In the context of early childhood education, drawing upon a cultural-historical perspective, we study how engineering pedagogical practices changed under the conditions of an intervention, called an engineering Conceptual PlayWorld (CPW). The findings show a shift in the focused teacher's subject positioning, and new practice contexts in which an engineering pedagogy emerged. We argue that a CPW created motivating conditions for Chinese kindergarten teachers to explore new engineering pedagogical practices, wherein they realised a new form of collective imaginary play and designed new engineering pedagogies for teaching young children.